Westerlund 2 cluster and nebula, Hubble Space Telescope (HST) image. The central region, containing the star cluster, blends visible-light data taken by the HST's Advanced Camera for Surveys (ACS) and near-infrared data from the HST's Wide Field Camera 3 (WFC3). The surrounding region shows optical (visible light) observations by the ACS. This open star cluster is 20,000 light years away, in the constellation of Carina. Image published in 2015.